1. Field of the Invention
This invention relates to a mower comprising a frame and a mowing group connected to said frame by a joint with a geometric axis directed at least approximately in the direction of advance at work, said frame comprising, on the one hand, a hitching element making it possible to hitch the mower to a tractor so that at work, the mowing group extends laterally on the side of the path of said tractor and, on the other hand, a support beam to whose outside end the mowing group is connected by the joint with a geometric axis directed approximately in the direction of advance at work, said support beam being connected to said hitching element by a hinged connection and a first connection element itself connected to the hitching element by a first joint and to the support beam by a second joint with a geometric axis approximately parallel to the geometric axis of the first joint, said mowing group being able, by pivoting around the joint with a geometric axis directed approximately in the direction of advance at work, to be brought to a transport position in which the mowing group is directed upward.
2. Background of the Related Art
Such a mower is described in FR-A-No. 2 240 679. In this known mower, the mowing group comprises a cutting bar equipped with four disks turning around axes directed upward. This known mower further comprises a frame making it possible to hitch it to a tractor. The mowing group is connected to this frame by a joint with an axis directed in the direction of advance. For this purpose, the frame is equipped with a yoke while the mowing group is equipped with a support element in the form of a transmission housing and able to pivot in the yoke around the axis directed approximately in the direction of advance.
The frame comprises a support beam and a hitching element. The mower is hitched by the latter to a tractor. This support beam is connected to the hitching element by a hinged connection and a first connection element. The hinged connection by which the support beam is connected to the hitching element consists of a simple joint with a vertical axis. The first connection element is formed by a safety tie rod whose length may be increased by pulling at its two ends. In this manner, the mowing group, in case it should hook an obstacle, can move together with the support beam relative to the hitching element by pivoting around the vertical axis of the hinged connection connecting the support beam to the hitching element.
In this known mower, the axis of the joint, by which the mowing group is connected to the support beam, extends by a certain distance outside the space requirement of the tractor. In addition, this axis extends by a certain distance from the ground. Thus, when the mowing group is brought by pivoting around this axis to its transport position, in which it extends upward, said mowing group exceeds by a not inconsiderable distance the space requirement of the tractor. This is disadvantageous in several respects as will be described later.
In FR-A-No. 2 255 839, another mower is described. In this known mower, the mowing group comprises a cutting bar equipped with six disks turning around axes directed upward. The disks extending to each end of the cutting bar are surmounted by a drum. This known mower further comprises a frame making it possible to hitch it to a tractor. The mowing group is connected to this frame by a joint with an axis directed approximately in the direction of advance, and extending by a certain distance outside the space requirement of the tractor. For this purpose, the frame is equipped with a yoke to which is connected in a hinged manner a support element forming part of the mowing group. This support element comprises a foot extending approximately horizontally to the back end of which is attached a leg extending approximately vertically. The foot is attached by its front end to the cutting bar and the leg is connected at its upper end to the frame by the joint with an axis directed approximately in the direction of advance. This support element extends in top view entirely behind the first disk. The disks and the drums of this known mower are driven in rotation by a drive shaft going through the drum surmounting the first disk. This drive shaft comprises two parts connected to each other by a flexible coupling. At its lower part, the drive shaft is connected in rotation, on the one hand, to the first disk and to the drum surmounting the latter and, on the other hand, to a cylindrical gear housed in a housing of the cutting bar. This cylindrical gear transmits the movement to a cascade of other cylindrical gears also housed in the housing of the cutting bar in order to assure the driving in rotation of the other disks and the other drum. The drive shaft itself is driven in rotation by an input shaft whose rotational axis is merged with the axis of the joint connecting the mowing group to the frame and by a pair of bevel gears extending to the vertex of the drive shaft and connecting it in rotation to said input shaft. This input shaft is driven in rotation by the power takeoff of the tractor by a device with a cardan shaft and belt pulleys. This known mower also comprises a hydraulic cylinder attached between the frame and the mowing group to bring the mowing group by pivoting around the joint to a transport position in which the mowing group extends upward.
This known mower exhibits the feature of having a mowing group whose overall width at ground level is equal to the cutting width. This is advantageous in several respects.
During the first passage, the mowing group does not bend the product to be harvested without cutting it. Further, during subsequent passages, it is not necessary to clear strips of ground wider than those necessary for the wheels of the tractor extending near the cutting bar. Since there is no part of the mowing group which exceeds, at ground level, the width of the cutting, risks of packing due to hooking of cut product to such a part are eliminated.
In transport, this known mower exhibits, however, the drawback of widely exceeding the overall width of the tractor. This is due to the fact that the axis of the joint connecting the mowing group to the frame extends above the drum surmounting the first disk, i.e. at a relatively significant height relative to the ground and, moreover, clearly outside the space requirement of the tractor. Thus, when the mowing group is pivoted in its transport position in which it extends approximately vertically, the mowing group extends laterally beyond the joint a distance equal to the value of said height.
In these known mowers, the overall width of the tractor-mower unit therefore is relatively great in transport. This can pose some problems for passing on narrow roads or through some farm entrance gates. This also poses visibility problems during driving. Since the center of gravity of the mowing group is relatively offset laterally, the frame of the mower and the hitching device of the tractor are stressed substantially. In addition, the wheels of the tractor extending on the side opposite to that where the mowing group extends are lightened substantially, which can pose problems of stability for low-power tractors.